Tidal Streams.

I began writing this entry in the Irish Sea as we worked our way directly in to a force 5 wind coming from exactly where we want edto go and happy about every bit of help we could get.

Most people know that the tide goes up and down. Pictures like the one below of boats sat on their side waiting for the tide to come in are common. But the water doesn’t just appear. It has to flow in to or out of the bay or harbour. Thieseflows are called tidal streams and can be a great help or hindrance depending on how well your planning works.

Fishguard at low tide

Fishguard at low tide

Today we spent the morning at anchor. We could have gone out but then the tidal stream would have been against us. By waiting until now we have the advantage of a huge “conveyor belt” carrying us in the direction we want to go. It is actually adding 0.7 knots to our speed right now and will continue to increase to 2 knots. This means that every hour we get about one to two extra miles. That may not sound like a lot but with us only making an average of four knots against the wind, we are glad of any help we can get.

A day after starting this blog entry I made a mistake in my calculations as a result of which we found ourselves passing between an island an a headland when the tide was against us. With sails up and the motor on, we were barely moving forwards. Another lesson in the importance of tidal streams

I learned all about tidal streams, calculating their effects and making use of them at sailing school but they are a lot more real when the mean the difference between gliding to your destination or fighting for every mile and anchoring before dark or not.

 

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